feat(python): add InputAligner

[dvorak0]

Summary

• add a Python InputAligner implementation for message_filters
• export it from the Python package
• add Python tests covering the same main behaviors as the C++ test_input_aligner.cpp

Notes

• this PR aims to mirror the semantics of include/message_filters/input_aligner.hpp in Python
• tests were added for ordering, inactive inputs, timeout handling, late drop behavior, timer dispatch, missing period information, and queue status
• this needs CI to validate the Python path in the target ROS environment